Michael Bloomberg’s ad campaign hasn’t done much to help his approval rating, which is down to 40 percent, according to a new poll from Marist and New York 1.

In February, when Marist last asked the question, 44 percent approved of Bloomberg’s job performance, which was an uptick from his all-time low of 37 percent in January, after the administration’s handling of the blizzard.

“Mayor Bloomberg is not immune from ‘third term-itis,'” said Dr. Lee M….